1. Field of the Invention
This invention relates to apparatus for preventing residual liquid from dripping from a spout.
2. Description of the Prior Art
There has long been the need for a device to prevent residual liquid, which clings to the inner walls of a spout, from dripping out of the spout. In particular, spouts used for dispensing high viscosity liquids may drip liquid for a long time after the major flow has ended. An example of this is a drum of oil in a mechanical shop. A hand pump is commonly used to draw oil from a drum. It is then dispensed through a downward-directed spout. After the proper amount of oil is dispensed, the container in which it is collected is withdrawn for carrying the oil to its intended destination. Residual oil clings to the inner wall of the spout and slowly drips on the floor. The oil spot on the floor is not only an unsightly dirt collector, but it creates an unsafe slippery spot. Moreover, a substantial amount of oil is wasted in this manner.
Some have tried to catch this residual dripping oil in a pan on the floor. The result is that the pan becomes the unsightly dirt collector. Oil captured in this manner is not clean enough for use and must be disposed of. In addition, the pan must sit exactly where it is most likely to be kicked over by the feet of those dispensing oil. What is needed is a device which will allow the pumping of oil through the spout, but which will retain residual oil until the next pumping occurs. No prior art device has been found which retains this residual oil within the spout.
U.S. Pat. No. 3,923,210 to Jackson, issued Dec. 2, 1975, shows a discharge regulator for use in a hydrocyclone. A pair of flexible sheets extends from the outlet on the hydroclone to allow passage of slurry, but to prevent the passage of liquid which contains no solid matter. The device is designed to allow passage of sand or other granular particles, but not liquid.
U.S. Pat. No. 3,995,780 to Showalter, issued Dec. 7, 1976, discloses a mechanism for discharging a slurry which has a valve actuated by a lever arrangement. The pressure needed to discharge slurry through the valve is dependent upon the weight acting upon the lever.
U.S. Pat. No. 3,129,894 to Schermerhorn, issued Apr. 21, 1964, discloses a nozzle guard for faucet spouts. The purpose of this guard is to provide a resilient surface so that dishes or glassware striking the nozzle will not break. One embodiment has a narrowing orifice which restricts the amount of flow.
U.S. Pat. No. 3,216,575 to Stuart, issued Nov. 9, 1965, discloses a check valve having a rubber sleeve which allows the flow of water into the sand bed of a filter apparatus, but which prevents backward flow.
U.S. Pat. No. 3,788,544 to Koskinenm, issued Jan. 19, 1974, discloses an agricultural irrigation system in which a check valve is employed to allow passage of water in one direction but to restrain somewhat its passage in the opposite direction. An elastometric cone-shaped section is slit to form opposed lips to allow the passage of water in one direction.
U.S. Pat. No. 3,269,664 to Lamb et al, issued Aug. 30, 1966, discloses a nozzle for discharging air into a liquid, such as in a bubbler used to prevent water from freezing. The valve has resilient lips which vibrate to form bubbles of air in the water. Air is discharged through the valve.
U.S. Pat. No. 3,199,787 to Oishei, issued Aug. 10, 1965, discloses a windshield washer system which has an elastometric nozzle. The nozzle is substantially tubular with a closed end having a transverse slit. The slit is designed to vibrate and break up the liquid into fine particles.
U.S. Pat. No. 3,107,035 to Cholet, issued Oct. 15, 1963, involves a squeeze cap for dispensing liquids from a container. A spherical valve sits in a valve seat to close a nozzle when it is not being squeezed.
U.S. Pat. No. 2,197,052 to Lowen, issued Apr. 16, 1940, discloses an applicator for fluid or viscous substance which includes a resilient rubber closure with a slit. Squeezing the tube opens the slit to allow the passage of liquid through the rubber cap.
U.S. Pat. No. 2,064,695 to Sipe, issued Dec. 15, 1936, discloses an air valve which includes a stem portion of soft rubber, with a slit. Air under pressure escapes through the slit, which seals to prevent backward flow.
Another air check valve is disclosed in U.S. Pat. No. 1,281,974 to Kaeding, issued Oct. 15, 1918, in which a pair of opposed flat jaws squeeze together an elastic tube. An elastic band aids in squeezing together the jaws so that the valve releases air under pressure but does not allow any backward flow.
U.S. Pat. No. 2,594,318 to Langdon, issued Apr. 29, 1952, discloses a check valve for preventing of backflow by using a check valve member made of flexible material with a slit.
U.S. Pat. No. 1,045,404 to Hottenroth, issued Nov. 26, 1912, discloses an air-tight check valve in which a tube has an opening which allows flow of air in one direction, but prevents back flow.
U.S. Pat. No. 3,060,882 to Peters et al, issued Oct. 30, 1962, shows a boat drain having a tubular elastomeric valve body with a flattened portion which allows the flow of liquid in one direction, but which is closed by the pressure of liquid in the opposite direction.
U.S. Pat. No. 2,513,272 to Bowen, issued July 4, 1950, discloses a dispensing valve for pressurized material which has a rubber valve member with transverse slits. The slits are opened by downward pressure on the spout.
U.S. Pat. No. 2,605,026 to Wagner, issued July 29, 1952, involves a cap for dispensing paste from a collapsible tube. The cap has a rubber compressible body with a slit which opens to allow dispensing of paste under pressure.
U.S. Pat. No. 2,576,192 to Poznik, issued Nov. 27, 1951, involves a venting attachment for gasoline tank filling necks. A check valve has flaps which are spread apart by the nozzle from which gasoline is dispensed. When the nozzle is removed, the flaps close to prevent escape of gasoline as a result of trapped air or frothing of the gasoline.
No prior art shows a device for preventing drips from a spout. What is needed is an apparatus which can satisfactorily allow the passage of liquid under pressure and yet retain liquid which is only under the pressure of gravity. A device must be economical and easily attachable to any downward pointing spout.
Applicant previously developed a drip retainer employing a tubular element of resilient material with a flattened portion made by biasing opposite walls of the tubular element together. This was the subject of U.S. patent application Ser. No. 781,188, filed Mar. 25, 1977, now abandoned. It was found that the tubular element did not maintain its flat state sufficiently to retain liquid.